I thought new iPhone day journey would be more fun with a road map. Here are a couple things I previously posted about moving to your new iPhone.
It appears the most important thing when using any backup from a previous iPhone is having your Apple Account password. If you don't know it but are logged into Apple device(s), depending upon your settings you can initiate a password reset. There are support documents to assist if you don’t have your password.
If you don't have space in iCloud for a full iCloud backup, Apple has provided temporary space for an iCloud backup to transfer to your new iPhone. There will be a "get ready for your new iPhone" under iPhone>Settings at some point, and it will offer the space there. When I used the iPhone Upgrade Program I had a “get ready for your new iPhone” in Settings, but I don’t see it yet this morning. Maybe it shows up when the new phone is turned on near the old phone.
I think the iCloud Restore started via Quick Start is probably the fastest and easiest method. And most people don't like transfers between devices as they lock you out of both devices until the process is complete. With iCloud Restore it will complete most of the transfer and then let you use the phone while it continues to download apps, email and messages, settings, and files.
One of my first steps after restoring to my new iPhone is to change my phone’s name in Settings>General>About
iPhone and Apple Watch setup articles
Some helpful Apple articles for setting up your new iPhone. I have them all open in tabs for consultation should i need any of them.
Use Quick Start to transfer data to a new iPhone or iPad
https://support.apple.com/en-us/102659
Restore your iPhone, iPad, or iPod touch from a backup
https://support.apple.com/en-us/118105
Use a wired connection to transfer data to a new iPhone or iPad
https://support.apple.com/en-us/117383?device-type=iphone
Apple Watch articles
Pair your Apple Watch with a new iPhone
https://support.apple.com/en-us/104956
If you can't pair your Apple Watch with a new iPhone
https://support.apple.com/en-us/122528
I did not find an article about pairing a new watch once you have the old watch paired with the new iPhone. As I recall I just started up the new watch next to the new iPhone and a notification on the iPhone asked if I wanted use the previous watch backup to set up the new watch.
Good luck and have fun out there!